Numerous methods have been employed to separate connecting rod preforms by fracturing, both in laboratory and production environments. These include cryogenic cooling or electron beam exposure to embrittle the fracture area, fracturing by wedge actuation of an expanding mandrel, and linear opposing pulling forces to separate the bearing cap from the connecting rod preform. The following patents are representative of the prior art:                U.S. Pat. No. 4,569,109, issued Feb. 11, 1986;        U.S. Pat. No. 4,768,694, issued Sep. 6, 1988;        U.S. Pat. No. 4,993,134, issued Feb. 19, 1991.        
Despite these prior developments, certain elements vital to fracture separation continue to have the greatest influence on the quality of the finished connecting rod. Two of these elements are:                (1) achieving simultaneous fracture along the cracking plane of both legs of the connecting rod. Failure to achieve simultaneous fracture is likely to result in plastic deformation of the crank bore and inhibit re-mating of the two parts;        (b) maintaining positive control over the position of the separated bearing cap and connecting rod body, to ensure accurate micro-alignment during re-mating. Failure to do this may negate the inherent advantages of fracture separation.        